This holder set is provided with: an optical bioinstrumentation holder which has at least two probe mounting units into which are inserted light-transmitting probes which irradiate light from the tip, or light-receiving probes which receive light from the tip, and which is mounted on the subjects head and a electroencephalograph holder which has at least one electrode mounting unit into which an EEG electrode is inserted which detects the potential difference with a reference electrode. This optical bioinstrumentation holder is provided with a linear trunk unit extending in a first direction, and at least two linear branches extending in a second direction different from the first direction, and the electroencephalograph holder is provided with a linear trunk unit extending in a first direction, and at least one linear branch extending in the direction opposite to said second direction.
